The audacious rescue plan that might have saved space shuttleColumbiaThe untold story of the rescue mission that could have been NASA's finest hour.

Enlarge / What might have been.

Lee Hutchinson / NASA / NOAA

If we die, we want people to accept it. We are in a risky business, and we hope that ifanything happens to us, it will not delay the program. The conquest of space is worth the riskof life.

—Astronaut Gus Grissom, 1965

It is important to note at the outset that Columbia broke up during a phase of flight that,given the current design of the Orbiter, offered no possibility of crew survival.

—Columbia Accident Investigation Board Report

At 10:39 Eastern Standard Time on January 16, 2003, space shuttle Columbia lifted off from pad 39A at theKennedy Space Center in Florida. A mere 81.7 seconds later, a chunk of insulating foam tore free from theorange external tank and smashed into the leading edge of the orbiter's left wing at a relative velocity of atleast 400 miles per hour (640 kph), but Columbia continued to climb toward orbit.

The foam strike was not observed live. Only after the shuttle was orbiting Earth did NASA's launch imageryreview reveal that the wing had been hit. Foam strikes during launch were not uncommon events, and shuttleprogram managers elected not to take on-orbit images of Columbia to visually assess any potential damage.Instead, NASA's Debris Assessment Team mathematically modeled the foam strike but could not reach anydefinitive conclusions about the state of the shuttle's wing. The mission continued.

In reality, the impact shattered at least one of the crucial reinforced carbon-carbon heat shield panels that linedthe edge of the wing, leaving a large hole in the brittle ceramic material. Sixteen days later, as Columbia re-entered the atmosphere, superheated plasma entered the orbiter's structure through the hole in the wing andthe shuttle began to disintegrate.

SCIENTIFIC METHOD / SCIENCE & EXPLORATION

by Lee Hutchinson - Feb 26, 2014 1:00 pm UTCSPACE

At Mission Control in Houston, the flight controllers monitoring Columbia's descent began to notice erratictelemetry readings coming from the shuttle, and then all voice and data contact with the orbiter was lost.Controllers continued to hope that they were merely looking at instrumentation failures, even as evidencemounted that a catastrophic event had taken place. Finally, at 9:12 Eastern Time, re-entry Flight Director LeRoyCain gave the terrible order that had only been uttered once before, 17 years earlier when Challenger brokeapart at launch: "Lock the doors."

It was an acknowledgement that the worst had happened; the mission was now in "contingency" mode. MissionControl was sealed off, and each flight controller began carefully preserving his or her console's data.

Columbia was gone, and all seven of its crew had been killed. NASA refers to this most rare and catastrophic ofevents as an LOCV—"Loss of Crew and Vehicle."

Frozen

Columbia is lost. There are no survivors.

—President George W. Bush in a national address, 14:04 EST, February 1, 2003

The world of human space flight paused—first to mourn, then to discover what had happened. Congress laidthat responsibility on the combined shoulders of the Columbia Accident Investigation Board (referred to, intypical NASA acronym-dependent style, as "the CAIB" or just "CAIB," which rhymes with "Gabe"). In the monthsafter Columbia, the CAIB stretched its investigative fingers all through NASA and its supporting contractors.

My own memories of the time immediately following the accident are dominated by images of somber meetingsand frantic work. I was a junior system administrator at Boeing in Houston, and because we supported theshuttle program, we had to locate and send cases and cases of backup tapes—containing everything thathappened on every server in our data center during the mission—over to NASA for analysis.

In August 2003, the CAIB issued its final report. Behind the direct cause of the foam strike, the report leveleddamning critiques at NASA's pre- and post-launch decision-making, painting a picture of an agency dominatedby milestone-obsessed middle management. That focus on narrow, group-specific work and reporting, without acomplementary focus on cross-department integration and communication, contributed at least as much to theloss of the shuttle as did the foam impact. Those accusations held a faint echo of familiarity—many of them hadbeen raised 17 years earlier by the Rogers Commission investigating Challenger's destruction.

In the end, Columbia's loss ended not only lives but also careers at all levels of NASA. A number of prominentshuttle program managers were reassigned. It is likely that Columbia's destruction factored heavily into theresignation of NASA Administrator Sean O'Keefe. Many involved with the mission—including many still workingat NASA—to this day struggle with post-traumatic stress and survivor's guilt. All pending shuttle missions wereput on hold, and Columbia's three surviving companion ships—Discovery, Atlantis, and Endeavour—weregrounded.

NASA looked inward, and we wondered if we'd fly again.

A path not taken

To put the decisions made during the flight of STS-107 into perspective, the Board askedNASA to determine if there were options for the safe return of the STS-107 crew.

—Columbia Accident Investigation Board Report

That's the way events actually unfolded. But imagine an alternate timeline for the Columbia mission in whichNASA quickly realized just how devastating the foam strike had been. Could the Columbia astronauts have beensafely retrieved from orbit?

During the writing of its report, the CAIB had the same question, so it asked NASA to develop a theoreticalrepair and rescue plan for Columbia "based on the premise that the wing damage events during launch wererecognized early during the mission." The result was an absolutely remarkable set of documents, which appearat the end of the report as Appendix D.13. They carry the low-key title "STS-107 In-Flight Options Assessment,"but the scenario they outline would have pushed NASA to its absolute limits as it mounted the most dramaticspace mission of all time.

NASA planners did have one fortuitous ace in the hole that made the plan possible: while Columbia's STS-107mission was in progress, Atlantis was already undergoing preparation for flight as STS-114, scheduled for launchon March 1. As Columbia thundered into orbit, the younger shuttle was staged in Orbital Processing Facility 1

(OPF-1) at the Kennedy Space Center. Its three main engines had already been installed, but it didn't yet have apayload or remote manipulator arm in its cargo bay. Two more weeks of refurbishment and prep workremained before it would be wheeled across the space center to the enormous Vehicle Assembly Building andhoisted up for attachment to an external tank and a pair of solid rocket boosters.

Enlarge / Endeavour undergoes processing at OPF-2. Atlantis was in a similar state while Columbia was

flying its final mission.

NASA

So an in-orbit rescue was at least feasible—but making a shuttle ready to fly is an incredibly complicatedprocedure involving millions of discrete steps. In order to pull Atlantis' launch forward, mission planners had todetermine which steps if any in the procedure could be safely skipped without endangering the rescue crew.

The desperate race

The scenarios were to assume that a decision to repair or rescue the Columbia crew would bemade quickly, with no regard to risk.

—Columbia Accident Investigation Board Report (Appendix D.13)

But even before those decisions could be made, NASA had to make another assessment—how long did it haveto mount a rescue? In tallying Columbia's supplies, NASA mission planners realized that the most pressing supplyissue for the astronauts wasn't running out of something like air or water but accumulating too much ofsomething: carbon dioxide.

Weight is a precious commodity for spacecraft. Every gram of mass that must be boosted up into orbit must bepaid for with fuel, and adding fuel adds weight that must also be paid for in more fuel (this spiral of mass-begets-fuel-begets-mass is often referred to as the tyranny of the rocket equation). Rather than carrying upspare "air," spacecraft launch with a mostly fixed volume of internal air, which they recycle by adding backcomponent gasses. The space shuttle carries supplies of liquid oxygen and liquid nitrogen, which are turned intogas and cycled into the cabin's air to maintain a 78 percent nitrogen/21 percent oxygen mixture, similar toEarth's atmosphere. The crew exhales carbon dioxide, though, and that carbon dioxide must be removed fromthe air.

To do this, the shuttle's air is filtered through canisters filled with lithium hydroxide (LiOH), which attaches tocarbon dioxide molecules to form lithium carbonate crystals (Li CO ), thus sequestering the toxic carbondioxide. These canisters are limited-use items, each containing a certain quantity of lithium hydroxide; Columbiawas equipped with 69 of them.

How long those 69 canisters would last proved difficult to estimate, though, because there isn't a lot of harddata on how much carbon dioxide the human body can tolerate in microgravity. Standard mission operationrules dictate that the mission be aborted if CO levels rise above a partial pressure of 15 mmHg (about twopercent of the cabin air's volume), and mission planners believed they could stretch Columbia's LiOH canistersupply to cover a total of 30 days of mission time without breaking that CO threshold. However, doing so wouldrequire the crew to spend 12 hours of each day doing as little as possible—sleeping, resting, and doingeverything they could to keep their metabolic rates low.

2 3

2

2

Enlarge

NASA / CAIB Report, Appendix D.13

If the crew couldn't sustain that low rate of activity, NASA flight surgeons believed that allowing the CO contentto rise to a partial pressure of 26.6 mmHg (about 3.5 percent cabin air volume) "would not produce any long-term effects on the health of the crewmembers." This would enable the crew to function on a more "normal"16-hour/8-hour wake/sleep cycle, but at the cost of potential physiological deficits; headaches, fatigue, andother problems related to the high CO levels would have started to manifest very quickly.

Enlarge

NASA / CAIB Report, Appendix D.13

After the carbon dioxide scrubbers, the next most limited consumable was oxygen. Columbia's liquid oxygensupplies were used not only to replenish breathing gas for the crew but also to generate power in the shuttle'sfuel cells (which combined oxygen with hydrogen to produce both energy and potable water). The amount ofliquid oxygen on board could be stretched past the CO scrubbers' 30-day mark by drastically cutting downColumbia's power draw.

The remaining three consumable categories consisted of food, water, and propellant. Assuming that the crewwould be moving minimally, food and water could stretch well beyond the 30-day limit imposed by the LiOHcanisters. To preserve propellant, the orbiter would be placed into an attitude needing minimal fuel to maintain.

Exactly when the crew of Columbia would enact these power- and oxygen-saving measures depended on ashort decision tree. In the scenario we're walking through, the assumption is that NASA determined on FlightDay 2 (January 17) that the foam strike had caused some damage, followed by at least another day to gatherimages of Columbia using "national assets" like ground-based telescopes and other space-based sources (i.e.,spy satellites) under the control of USSTRATCOM.

2

2

2

Enlarge / "FD" is short for "Flight Day."

NASA / CAIB Report, Appendix D.13

If that imagery positively identified damage, Columbia would immediately enter power-down mode; if theimages didn't show anything conclusive, the crew would conduct an EVA (extra-vehicular activity—a spacewalk)to visually assess the damage to the wing, then power things down.

In either case, Flight Day 3 would mark the start of many sleepless nights for many people.

No do-overs, no mistakes

This rescue was considered challenging but feasible.

—Columbia Accident Investigation Board Report

Planning the inspection EVA would have taken most of Flight Day 4 (January 19), but the hard deadline of thelithium hydroxide canisters remained set at Flight Day 30 (February 15) regardless of what happened on theground. Work would simultaneously have had to begin at the Kennedy Space Center to accelerate theprocessing of Atlantis.

"Accelerate" is a prosaic word for the herculean effort that would have been needed. Activities that normallytake place across weeks or months would have to happen in hours or days. Civil servants and contractors atKSC would have to begin 24/7 shift work, keeping the lights on and the process running every hour of every day,for a minimum of 21 days, to power Atlantis through checkout and make it ready to launch.

Three unceasing, brutal weeks of 24/7 shift work—and that's with absolutely no margin factored in for errors orfailures. The Orbital Processing Facility team, the Vehicle Assembly Building team, and the Launch Complex 39pad team would have had to get every one of the millions of steps right, and every component of Atlantis wouldhave had to function perfectly the very first time, or it would all be wasted.

Enlarge / A rescue mission would require preparing a shuttle for launch far faster than had ever been

done before.

NASA / CAIB Report, Appendix D.13

So many things would have to happen. First, Atlantis' computers would have to be reprogrammed toaccommodate the changes in the mission. Fortunately, the flight software developed for STS-114's InternationalSpace Station (ISS) rendezvous could be adapted to instead rendezvous with Columbia, though most of thespecific rendezvous parameters would have to be altered. The changes would be uploaded toAtlantis' computers during the DOLILU—the Day of Launch Input Load Update, the standard last-minutesoftware update that shuttles on the pad receive two hours prior to launch. Usually, DOLILU loads include flightcontrol updates to accommodate the day's observed weather patterns, but this particular DOLILU load would

change the entire flight profile. It would be the largest on-pad software update ever attempted.

In order to push Atlantis through processing in time, a number of standard checks would have to be abandoned.The expedited OPF processing would get Atlantis into the Vehicle Assembly Building in just six days, and the 24/7prep work would then shave an additional day off the amount of time it takes to get Atlantis mated to itsexternal tank and boosters. After only four days in the Vehicle Assembly Building, one of the two Crawler-Transporters would haul Atlantis out to Launch Complex 39, where it would stage on either Pad A or Pad B onFlight Day 15—January 30.

Enlarge / Under troubled skies, Atlantis makes its way out to the pad atop one of the Crawler-

Transporters to embark on STS-129.

NASA / WikiMedia Commons

Once on the pad, the final push to launch would begin. There would be no practice countdown for theastronauts chosen to fly the mission, nor would there be extra fuel leak tests. Prior to this launch, the shortesttime a shuttle had spent on the launch pad was 14 days; the pad crews closing out Atlantis would have only 11days to get it ready to fly.

Even as workers at Cape Canaveral frantically tried to beat the clock, more work had to happen at the JohnsonSpace Center in Houston: Atlantis still needed a crew.

The right stuff

[I]t would be important to have a high degree of confidence in the astronautsʼ ability toquickly adapt to the micro-gravity environment.

—Columbia Accident Investigation Board Report (Appendix D.13)

Columbia carried seven astronauts, who by Flight Day 15 would be halfway through their unexpectedlyextended 30-day mission. This presented a problem for NASA: space shuttles were designed to accommodatefive to seven astronauts, and Atlantis would need its own crew in order to launch and rendezvous with Columbia.When Atlantis returned, it would carry not only the astronauts it launched with, but also Columbia's rescuedcrew—so to minimize crowding, what was the minimal crew count Atlantis could get away with at launch?

After analysis, it was determined that Atlantis would need a minimum crew of four. A two-person pilot andcommander team would be required to actually fly the rendezvous and actively keep station with Columbia—which NASA estimated would mean at least eight or nine hours of manual flying (and potentially much morethan that). Another two-person team would be required to don suits and perform the rescue EVA tasks—taskswhich NASA would have had to design from scratch.

As with every other task involved with the rescue, there was no room for error, and there would be no secondchances. Atlantis would be launched with an all-veteran crew, with selection for the mission biased heavilytoward astronauts who demonstrated fast adaptation to microgravity (there was no time to be space-sick) andhigh aptitude at EVA and rendezvous. The report names no names, but it does indicate that an assessmentrevealed a pool of nine EVA candidates, seven command candidates, and seven pilot candidates available inJanuary 2003 whom NASA felt could have undertaken the mission.

Further Reading

SWIMMING WITH SPACEMEN:SWIMMING WITH SPACEMEN: TRAININGFOR SPACEWALKS AT NASA’S GIANT POOL

To do construction 200 miles up, you must

first go deep underwater.

The four astronauts chosen to fly Atlantis would have faced anextraordinarily compressed training schedule—and also a tremendousamount of professional and personal pressure. The tight timeline wouldmean that the two Atlantis astronauts selected to actually spacewalkbetween the shuttles for the rescue EVA would likely be trainingunderwater at NASA's Neutral Buoyancy Lab almost every single day ofthe two weeks, breaking the entire multi-hour spacewalk up into tinycomponent maneuvers and procedures and walking through each tocommit them to memory. Simultaneously, the two astronauts selected topilot the shuttle would have spent that time in the large motion-basesimulators in Building 9 at the Johnson Space Center, working throughevery moment of the rendezvous, station-keeping, and landing fromstart to finish.

Enlarge / Looking down into NASA's Neutral Buoyancy Lab pool from one of the test director control

rooms.

Steven Michael

It's also certain that the media would have exerted its own tremendous pressure, attempting to thrust camerasand lights into every corner of the preparation—as much as they would be allowed to do so, anyway. "Spacedisaster" and "rescue mission" are golden ratings words. Clear Lake in Houston and Cape Canaveral in Floridawould have been swarmed with TV trucks; the Johnson Space Center sign on historic NASA Rd 1 would likelyhave been a constant backdrop on TV news both local and national.

And throughout the frantic weeks on the ground, Columbia's crew would wait.

Slow time

This powerdown would have supported only the most basic vehicle control and crew supportand communication equipment.

—Columbia Accident Investigation Board Report (Appendix D.13)

While work on the ground would proceed in a controlled frenzy, time on Columbia would lengthen and draw outin slow misery. The crew would have potentially undergone a brief flurry of activity if they needed to do an EVAto confirm the damage to the orbiter's left wing; additionally, they would have needed to maneuver Columbiainto a tail-first "gravity gradient" attitude so that the Earth's pull on the shuttle's empennage would keep theorbiter's orientation fixed relative to Earth without the need to expend any propellant. After that, though, thestranded crew could do very little other than wait and try not to move or breathe too much.

Enlarge / STS-107 mission specialists Laurel B. Clark, Rick D. Husband, and Kalpana Chawla relaxing in

their bunks on Columbia's middeck.

NASA / WikiMedia Commons

The crew wouldn't even be able to watch their own rescue's TV coverage, because the orbiter would be in atightly restricted low-power mode in order to conserve its energy. Appendix D.13 includes a description of whatsystems would be shut down, and among them are "all cameras, camera heaters, TV monitors, and videoequipment."

An oft-asked question is whether or not Columbia could have docked with the ISS, which would have hadconsumables to spare. There are numerous reasons why this would not have been possible, but the overridingone comes down to simple physics: Columbia would have had to execute what is known in orbital mechanicsterminology as a "plane change" maneuver—applying thrust perpendicular to its orbital track in order to shift tomatch the ISS' inclination. Plane change maneuvers require tremendous amounts of energy—in some cases,even more energy than was required to launch the spacecraft in the first place. Appendix D.13 dismisses thepossibility of an ISS rendezvous with just two sentences:

Columbia's 39 degree orbital inclination could not have been altered to the ISS 51.6 degree inclinationwithout approximately 12,600 ft/sec of translational capability. Columbia had 448 ft/sec of propellantavailable.

The crew would be playing the long game, carefully conserving resources for the burst of activity that wouldhave to occur at the end of the mission. As previously noted, the primary consumable of consequence would bethe carbon dioxide scrubbers, so rest and sleep would have been the crew's main mission. Columbia's orbitalperiod would mean that during their quiet exile, the crew would see more than 300 sunrises break over thecurving lip of the world.

How long would it feel? How many card games can you play? How many jokes or stories can you tell? How manytimes do you turn the proposed rescue over in your mind while you sit in a sleeping cubicle, unable to bathe andsurrounded by your own stink and the stink of six other tired and scared people, counting each of the 30,000interminable minutes?

It would have been more than 20 days of endless, drifting purgatory.

Russian roulette

This new risk to the Orbiter would weigh heavily in the decision process on launching anothershuttle and crew.

—Columbia Accident Investigation Board Report (Appendix D.13)

Appendix D.13 is written under the assumption that the damage to Columbia's wing was recognized and actedupon, but that is actually the first of two major assumptions underlying the rescue mission. The secondassumption has its own set of enormous issues: given that Columbia was disabled by a foam strike, NASA wouldhave to be willing to subject Atlantis to the exact same risk.

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NASA / CAIB Report, Appendix D.13

The obvious terrifying question here is whether or not there wasanything NASA could do in the near term to prevent Atlantis from beingdisabled by the same type of foam impact—and the answer is a quietno.

The foam chunk that sheared off of Columbia's external tank was partof what's called the left "bipod ramp," one of two hand-sculptedstructures flanking the large bipod struts that secure the orbiter's noseto the forward part of the external tank. To form the bipod ramps,orange BX-250 insulation is sprayed over the fittings that attach thebipod to the external tank. It's allowed to dry, then it's shaved by handinto wedges that cover the fitting elements. Coupled with a layer ofablative materials atop the fittings, the foam ramps both protect theattachment points from heat during launch and also sheath them in anaerodynamic shape.

And, as it turns out, bipod ramps broke off six times before STS-107.

Enlarge

NASA / CAIB Report, Appendix D.13

Much of the CAIB report is given over to discussing the specifics of the external tank's insulating foam—what it'smade of, how that material performs, and how often foam has sheared off of the ET and impacted with anorbiter. What is clear from the report is that the STS-107 foam strike was not a unique event—it was a relativelycommon occurrence that in this particular instance occurred at precisely the right (or wrong) time to causecatastrophic damage to one of the very few things on the shuttle without any form of redundancy.

The Atlantis rescue mission would face the exact same vulnerability. It would fly with an already-preparedexternal tank, and as the Appendix clearly states in the scenario outlined, Atlantis would fly without any timeadded to the processing schedule to perform any assessments or repairs on the external tank used.

This is another reason why the rescue crew would be made up of four astronauts instead of launching withmore crew—to expose as few humans as possible to the risk of death.

Gravity ballet

Success Criteria: The safe return of the rescue vehicle (Atlantis) and both crews.

—Columbia Accident Investigation Board Report (Appendix D.13)

There would have been three launch windows during which Atlantis

Enlarge

NASA / CAIB Report, Appendix D.13

There would have been three launch windows during which Atlantiswould be able to launch and reach Columbia; one at 23:09 EST onFebruary 9 (Flight Day 25), another at 22:40 EST the next day, and afinal one the day after that at 22:05 EST. Columbia would be madeready to meet its companion ship three days prior to the first launchwindow. The crew, potentially suffering from the effects of carbondioxide poisoning, would revive the shuttle's systems enough to push itinto a slightly elliptical higher orbit, which would give Atlantis a betterset of opportunities to make the rendezvous.

Any of the three launch windows would have provided a working marginto reach Columbia before its supply of carbon dioxide scrubbers wasexhausted, but earlier was obviously better. The first launch windowprovided a substantially earlier rendezvous time on February 10; thelatter two windows both meant a rendezvous on February 13. The laterrendezvous time would leave, at most, 36 hours of margin beforeColumbia could no longer support life.

Weather is one of the major unknowns when planning a shuttle launch—not just at the launch site but also at the multiple places around theworld that must be kept ready for an emergency landing if the orbiterneeds to abort its attempt to reach orbit. The CAIB report shows thatluck would have been on NASA's side here; a review of observedweather conditions on the proposed launch days showed that there wasnothing happening in the atmosphere that would have hindered thelaunch.

More worrying, though, was that the three windows all opened at night. A night launch would substantiallyreduce NASA's ability to observe foam damage during Atlantis' flight to orbit, which was particularly ominous inlight of the reason behind the rescue mission. Because of this, an additional EVA was added for Atlantis' crewafter reaching Columbia—they would carefully examine Atlantis' wings and tiles for any damage.

Enlarge / Endeavour lifts off from pad 39A for STS-130 in February 2010. This was the final night

launch of the space shuttle program.

NASA

Assuming all went well and there were no countdown delays, Atlantis would have lifted off on the evening ofFebruary 9, 2003. At that point, Columbia's crew would have long since set a shuttle program record—theywould have been in space for 25 days, eight days longer than the previous longest shuttle mission. In order tolower the nitrogen content in their blood and be ready to don their suits as soon as possible, the two EVA crewon Atlantis would possibly have been required to breathe pure oxygen from the moment they entered theorbiter's cabin on the launch pad.

Enlarge

NASA / CAIB Report, Appendix D.13

Enlarge / Endeavour on approach to the ISS, showing details of forward flight deck windows, upper

flight deck rendezvous windows, and airlock docking assembly aft of the flight deck.

NASA

Atlantis would arc upward into orbit, approaching Columbia from belowin what's called an "R-bar approach"—that is, an approach along animaginary radial line connecting Columbia with the Earth's center.(Contrast this to a V-bar approach, which would be an approach alongColumbia's velocity vector—that is, from the front or back, rather thanthe top or bottom.) Columbia would already be oriented tail-first and"upside down" relative to the earth; Atlantis would approach "right sideup" beneath it. Atlantis would swing slowly up into place, each shuttlegrowing larger and larger in the rendezvous windows in their respectiveflight decks' ceilings.

Finally, Atlantis would ease to a halt 20 feet (six meters) from Columbia.Atlantis would be yawed 90 degrees to Columbia, pointing at threeo'clock to the older orbiter's 12 o'clock, in order to keep their verticalstabilizers from striking.

Enlarge / Atlantis keeps station below Columbia.

NASA / CAIB Report, Appendix D.13

This would have been the first time two space shuttles were simultaneously orbiting, and the challenges wouldhave been considerable. Each shuttle would have its own flight control room operating in NASA's Mission Control

Center—and, with the ISS also requiring a flight control room, this would have tasked the control center tocapacity (both from a perspective of technical and human resources). Moreover, Atlantis would have needed tobe under constant manual control for the duration of the rendezvous, because even at a distance of 20 feet,orbital mechanics would keep the two spacecraft moving at different velocities and they would drift apart inshort order, with Atlantis at the lower altitude constantly trying to race ahead of Columbia.

Enlarge / Space shuttle cockpit mockup from the CCT-2 (Crew Compartment Trainer) at NASA's Space

Vehicle Mockup Facility. The middle console contains most of the attitude and translation controls

Atlantis' commander and pilot would have used to fly the rendezvous with Columbia.

Steven Michael

While Atlantis' pilot and commander settled in to trade off the task of holding the shuttle steady for nine hours,the other two crew—called "EV1" and "EV2" in the report—would already be suited and standing by in theairlock. As soon as they were given a "go," EV1 and 2 would open Atlantis' airlock and retrieve an expandableboom, with which EV2 would assist EV1 in moving across the gap to Columbia. Extra lithium hydroxide canisterswould also be transferred between the two shuttles to give Columbia some breathing room—literally—alongwith a pair of spacesuits for Columbia's crew to wear. Incongruously, the Appendix notes that the suits wouldneed to be transferred, "powered up, and pressurized" to preserve their water supplies, which would no doubtlook quite odd.

Enlarge / NASA animatic showing Atlantis EV1 and EV2 in the gap between the two shuttles' cargo

bays. EV2's feet are fixed in a portable foot restraint, and the astronaut is moving EV1 across the gap

with a boom.

NASA / CAIB Report

Two undoubtedly stir-crazy Columbia crewmembers (referred to as "CM1" and "CM2") would already be suitedand waiting in Columbia's airlock to assist in the transfer from Atlantis. EV1 would parcel the supplies from

Atlantis into Columbia's airlock, then assist CM1 and CM2 out of the airlock and help them negotiate the pathback to Atlantis.

Shell game

There would be a number of activities that would be attempted for the first time during thisconceptual inspection and rescue mission.

—Columbia Accident Investigation Board Report (Appendix D.13)

From here, the complexity of the mission begins to ratchet up to maximum. Depending on how tired andcompromised they were physically, "CM1" and "CM2" could help spell the Atlantis pilot and commander at theirstation-keeping exercises (assuming that CM1 and CM2 were Columbia commander Rick Husband and pilotWilliam McCool), but the two extra space suits would be put to considerable use.

Atlantis' two EVA crewmembers would remain outside, and while CM1 and CM2 were removing their suits, thetwo Atlantis crew would use their SAFER jet packs to check over Atlantis' tiles and leading edges for damage(Columbia lacked SAFER packs, and the inspection EVA its crew would have gone through would have involvedmuch more strenuous techniques to clamber along the orbiter's structure and get a look at the wing).

CM1 and CM2 would remove their suits and then get them ready for reuse; they would be returned by EV1 andEV2 to Columbia and stashed in the airlock, which would then be pressurized and opened. Two more Columbiacrewmembers would already have donned the spare suits shuttled over earlier and thus become CM3 and CM4,and the same procedure would be repeated as with CM1 and CM2.

Enlarge / Another view of the crew transfer between Columbia and Atlantis.

NASA / CAIB Report, Appendix D.13

The report spells out a best-case scenario where the suit donning and doffing goes off without a hitch, and inthat case, all the transfers could be done without stopping for a break. This would mean that Atlantis' EV1 andEV2 crewmembers would be outside for somewhere between 8.5 to nine hours in a single EVA.

However, that outcome is hardly a given. Putting on a space suit is a complex procedure on the ground, in fullgravity and with multiple sharp-eyed assistants helping out. Putting on a suit in Columbia's middeck, possiblywhile still attempting to shake off the effects of carbon dioxide poisoning, is a much dicier operation. It's madeeven more complicated by the fact that for each successful crew transfer, the number of helpers is reduced. It'spossible that the operation would have stretched to multiple EVAs—instead of nine hours, it could have takenmore than three times as long.

After the first two two-person transfers, the next transfer would consist of a single person: CM5 would go acrossalone, with EV1 and EV2 assisting. This would be done because Columbia had a crew of seven, and one personwould have to do the transfer by themselves. Leaving the last two crewmembers, CM6 and CM7, to operate as apair at least meant that the two would have had each other's assistance in donning the well-used spacesuits. Ars

consulted a number of sources to gauge the difficulty of donning spacesuits without any assistance fromunsuited crew. Though none would speak on record, the consensus is that it would involve what was universallycategorized as an extremely high degree of difficulty.

Shooting star

There would be no possibility of recovering Columbia.

—Columbia Accident Investigation Board Report (Appendix D.13)

Prior to their exit, the last two members of Columbia's crew would have some final tasks to carry out. Theorbiter would need to be readied to be placed under ground control so that it could be deorbited.

There was no chance of recovery for the shuttle itself. Even if the wing could have been patched and cold-soaked and the shuttle's reentry profile altered to raise the reentry angle of attack and lower the temperatureat the wing leading edge, it is unlikely that it would have survived. Further, even if successful reentry werepossible, the shuttle could not be landed entirely from the ground—there was no way for Mission Control to haveextended the shuttle's landing gear or the air probes necessary to judge velocity once in the atmosphere. Thosefunctions (as well as starting the shuttle's auxiliary power unit) could only be invoked by physically throwingswitches in the cockpit during approach and landing.

The remaining shuttle fleet gained the ability to land totally under ground control in 2006, with the developmentof the RCO IFM cable, a 28-foot (8.5-meter) braided cable that the crew could use to physically link the cockpitwith the shuttle's avionics bay and patch Mission Control into the required switches.

Enlarge / The landing gear switches (left) are in front of the commander's station. They are among the

few systems that could not be operated remotely by ground control.

Steven Michael

For Columbia, this wasn't an option. CM6 and CM7 would have had to proceed to the shuttle's flight deck andtoggle a number of switches into place, giving Mission Control on the ground direct command of Columbia'sguidance and maneuvering systems.

CM6 and CM7 would then depart, sealing the airlock behind them and leaving Columbia to find its own wayhome. Atlantis would back slowly away from its sister ship, and its crew of 11 would busy themselves preparingfor their own crowded reentry ordeal—never before has an orbiter landed with 11 crewmembers, and evensimple things like seating would be complicated. Some crew would literally have to sit strapped to the floorduring reentry.

At some point over the next few hours or days, ground controllers would command Columbia to close its cargobay doors and orient itself for what would be its final task. The shuttle would roll its damaged thermal tiles toface Earth and perform a retrograde burn with its large OMS engines. Shortly after that, it would cross the entryinterface.

Contrary to popular belief, the heat a spacecraft faces on reentry isn't generated by simple friction but ratherby ram pressure—the fast-moving shuttle compresses the air in front of it, forming a massive shock zone inwhich air molecules ionize and break apart. As Columbia descended, an observer on the flight deck would see

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the windows glow and flare with plasma. After a short time, that plasma would invade the shuttle's structurethrough the hole in its wing.

Columbia's last act would be to brighten the sky over the South Pacific, first as one glowing star and thenbreaking apart into many. The remains of the oldest shuttle would pepper the surface of the Pacific, and itwould be no more.

Enlarge / Glowing, ionized trail from Atlantis' re-entry on the final flight of the space shuttle program.

Photographed from the ISS on July 21, 2011.

NASA

Ad astra per aspera

It should be noted that although each of the individual elements could be completed in a best-case scenario to allow a rescue mission to be attempted, the total risk of shortening trainingand preparation time is higher than the individual elements.

—Columbia Accident Investigation Board Report (Appendix D.13)

We all love Hollywood endings, but it's difficult to envision the rescue mission coming together with the requiredlevel of perfection. For example, in researching this article, I was unable to discover the number of times ashuttle has gone through an Orbital Processing Facility, Vehicle Assembly Building, and launch pad processingflow with no errors or faults. Based on the complexity of the machine, I suspect that it has never happenedbefore.

And yet, when faced with a challenge of this magnitude and with suchtremendous consequences, it's incredibly attractive to imagine NASArising to the task. As an agency, NASA simultaneously represents thebest and worst of the United States of America—it is responsible forsome of the greatest engineering achievements in the history ofhumankind and has accomplished a long list of goals originally deemedimpossible. At the same time, the agency is also crippled by a lack ofdirection and leadership; it has gone from being an organization capableof putting human beings on other worlds to an organization that lackseven the means to put them into low Earth orbit without assistance.

The mission to rescue Columbia, though, represents the kind of task thatNASA, since its beginnings, has demonstrated an unswerving ability toexecute. There would have been a clear goal, there would have beenhard timing requirements, and the agency's massive pool of engineeringtalent would be empowered to accomplish the goal at any cost and without restriction.

The will to win would not be lacking, but technical challenges are ignorant of will and drive—look, for example,at the liquid oxygen tank explosion that crippled the Apollo 13 command and service module in 1970. Thatexplosion was the result of a combination of events that occurred prior to launch, with potential blamestretching from the tank's manufacturer all the way to the crew itself. The error-free rescue of Columbia wouldhave depended not just on the flawless execution of teams at all of the NASA centers but also on an unknown

number of events that happened days, weeks, months, or even years in the past leading up to the mission.

In researching this article, I spoke with a large number of current and former NASA personnel, both inside andoutside of the Missions Operation Directorate. All were polite, but none would talk on-record about the feasibilityof the proposed Atlantis rescue mission. The formal response I received from NASA's Public Affairs Officerespectfully but firmly informed me that the CAIB report is NASA's full and official statement on the matter:

From NASA’s standpoint, there is nothing further to add to the Columbia Accident Investigation Report(Chapter six and its appendices) related to the "what if" scenario of rescuing the STS-107 crew. As you areaware, it is spelled out very clearly that there would have to have been a very large number of "knowns" tohave executed a rescue or repair mission for Columbia at that time.

...

Beyond that, we respectfully decline any specific interviews on the subject and reference you to the CAIBreport for the detailed analysis provided during the investigation of the Columbia accident.

Ultimately, Appendix D.13 is a well-informed, research-backed exercise in speculation, constructed by engineerswho were intimately familiar with shuttle program operations. My telling of the rescue's story is not intended tocriticize or damn NASA for its actions, nor am I attempting from a position of historical privilege to second guessthe decision-makers who to this day must live with the grave consequences of the choices made. Columbia andits crew almost certainly could not have been rescued without too many "ifs" having fallen the other way. I cantell the story of what might have been the most awe-inspiring moment in all of human space flight, but I amprofoundly unqualified to speculate beyond the boundaries of the CAIB report.

It's an amazing story—but it's only a story.

The long road back

It is unlikely that launching a space vehicle will ever be as routine an undertaking ascommercial air travel—certainly not in the lifetime of anybody who reads this. The scientistsand engineers continually work on better ways, but if we want to continue going into outerspace, we must continue to accept the risks.

—Columbia Accident Investigation Board Report

It took 907 days after Columbia's destruction for NASA to return to flight. STS-114—flown by Discovery insteadof Atlantis—lifted off from the Cape on July 26, 2005. I remember it very well—now as a not-so-junior systemadministrator, I watched helplessly as the sheer number of Boeing employees streaming the countdown andlaunch video from NASA TV saturated our site's Internet link, which somewhat hilariously almost caused sitemanagement to try to request a launch hold (Boeing's Houston office provided shuttle support, and some ofthose support activities needed that same Internet link to function). The launch was a success.

Starting with STS-114, no shuttle would fly without a rescue shuttle on standby. These planned emergencyflights (numbered STS-3xx) were called LON missions, for "Launch On Need." In the event of trouble on a shuttlemission, crews would rendezvous with the ISS and shelter there for up to 50 days, while the LON shuttle wouldbe made ready to fly to retrieve them.

The one exception to this was the final Hubble servicing mission, STS-125. The orbital height and inclination ofthe Hubble made the mission totally incompatible with an emergency ISS rendezvous in the event of trouble, soa plan based partially on the Atlantis/Columbia rescue was drafted. The STS-125 LON mission would have beendubbed STS-400. Because the ISS wasn't available, STS-400's Endeavour needed to be ready to launch on shortnotice; this led to the final instance of what was already a rare sight: two shuttles staged at LC-39simultaneously.

Enlarge

NASA / WikiMedia Commons

The LON missions were never needed, and the shuttle program finished without any other significant incidents.Foam strikes were not eliminated, but post-launch analysis of each shuttle was increased. It is a virtual certaintythat future NASA manned spacecraft will return to their rightful place on top of launch vehicles rather thanbeing slung on their sides. NASA's culture continues to evolve; it is impossible to say at this point if the lessons ofColumbia have been fully inculcated into the agency.

I was there for the aftermath and the return to flight, but agency-wide policy changes are things that happenedfar above my pay grade. The thing I remember more than anything else, the single most vivid memory of themall, is of the memorial service the Tuesday after Columbia's destruction.

February 4, 2003

This cause of exploration and discovery is not an option we choose—it is a desire written inthe human heart. We are that part of creation which seeks to understand all creation. Wefind the best among us, send them forth into unmapped darkness, and pray they will return.They go in peace for all mankind, and all mankind is in their debt.

—President George W. Bush, addressing personnel at the Johnson Space Center

We arrived at the Johnson Space Center at about 9:30am, having been told that space would be limited for theservice, which was to start at noon. After a half-mile of walking and a security checkpoint, we stood in thecentral mall by Building 16, lost amid a sea of people. The stage and podium were far away on the other side ofthe grassy field, and we passed the two-and-a-half hours in uncomfortable, standing silence. After a long wait,Air Force One, trailed by three F-15s, circled on its way down to Ellington Field. The crowd swelled to itsmaximum just after 11. At noon, with no fanfare, President Bush and First Lady Laura Bush walked together totheir place on the stage. They held hands, which stuck in my mind—even the most powerful man in the worldholds hands with his wife.

There was an invocation, and then words from NASA's director and the chief of the Astronaut Corps. Both paidtribute to each astronaut individually, and the Corps chief clearly had to fight to keep back tears. The presidentstepped to the podium next and spoke eloquently about the human spirit. The only even vaguely political wordsthat left his mouth were ultimately topical—he said that the space program would continue. Then he, too, spokeof each astronaut individually, praising their daring and dedication.

A ship's bell tolled seven times, once for each of Columbia's crew, and then four NASA T-38s flew over in themissing man formation. The jets moved in low and fast, streaking toward us in a wedge less than 250 feet offthe ground. As they passed overhead, the second jet back on the left side of the formation peeled sharplyupward, right as the roar of the engines hammered at us. The missing man jet arched high and straight as theformation continued onward, now with an empty spot to recognize that there were men and women who wereno longer with us.

I have never before witnessed anything so profoundly moving as that trio of jets hurtling low over the rest of thecampus, with their missing comrade thousands of feet above and rocketing higher still. I will remember it

forever.

Godspeed, Columbia.

Enlarge

Lee Hutchinson / Lee is the Senior Reviews Editor at Ars and is responsible for the product news and reviews section. He also knows stuff aboutenterprise storage, security, and manned space flight. Lee is based in Houston, TX.@Lee_Ars

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EDITOR'S PICK: PROMOTED READER COMMENT

jump to postSTS_EngineerSmack-Fu Master, in training

I worked on the planning for the STS-125 rescue mission, STS-400. It took 18 months of planning to develop the procedures, modifythe tools, test and simulate the GN&C, EVA, and robotics choreography, and prepare all the paperwork to satisfy everyone that itwas a safe plan for both orbiters and the crew. The proposed plan in this article would have been even more difficult because therewas no opportunity to use the RMS (robotic arm) to grapple Columbia. Columbia wasn't carrying an arm, and Columbia itself didnot have a grapple fixture that Atlantis's arm could use. I am extremely dubious that the manual station keeping would be doableeven just from a propellant standpoint: STS-400 had the crew transfer requiring two days. (The STS-400 timeline is availableonline) For Columbia, that would mean manually station-keeping for an entire EVA (6.5 hours), then separating until the next EVA isready, and performing another rendezvous and station keeping for > 6.5 hours. I don't think there is anywhere near enough RCSfuel to do that.

The only hope that this plan would have ever had would have been if the plan had already been in place prior to Columbia's launch,as there is no way on this Earth that NASA would have approved a flight with untested procedures that could destroy both orbiters.As I said above, the very similar STS-400 flight planning took 18 months; even if the entire NASA work force worked around theclock, that amount of work wasn't going to happen in just a few weeks. Sadly, I can't see a path where this would have actuallybeen feasible.

1 post | registered Feb 26, 2014